Protected pin retention device for crawler track assembly

ABSTRACT

An articulated endless track for a mobile machine has a plurality of crawler pads connected in series. Each adjacent pair of pads has spaced apart hinge knuckles engaged in alternating fashion to form a hinge pin chamber. Each chamber contains a hinge pin positioned between a pair of retention elements. Each retention element is secured to its associated encircling hinge knuckle. This arrangement protects the retention elements against abrasion while permitting assembly or disassembly of the track to be accomplished readily.

FIELD OF THE INVENTION

This invention relates to articulated endless track assemblies, such asused on mobile mining machinery to move the machinery from one locationto another. In one aspect the invention relates to means for retainingthe track hinge pins in place and means for protecting the retainingmeans against abrasive contact with the ground during movement of thetrack. In another aspect, the invention relates to means for readilyassembling or disassembling the track in a confined area.

BACKGROUND OF THE INVENTION

An articulated endless track for track-type vehicles comprises aplurality of crawler pads connected in series with each other, with eachpair of adjacent pads being pivotally joined together by means of ahinge pin. If the hinge pin is retained in place by being press fittedinto bushings in one of the pair of adjacent pads, it can be difficultto remove the pin in a confined area such as an underground mine. If thepin is not secured to either pad, then means must be provided to retainthe pin in place. One commercial retention technique utilizes twocoaxially aligned hinge pins in each hinge connection of two crawlerpads in an articulated endless track, the ends of the pins at the centerof the track being exposed, and a lock pin being secured in a holecross-drilled in the exposed inner end of each hinge pin. However, theselock pins are located such that they are exposed to the high-wearoperating environment. Another commercial retention technique employs ascrew/lock nut arrangement on each side of the track. The screw islocated in a flange which extends outwardly from the side of the crawlerpad so that the nut is positioned adjacent the end of the hinge pin.However, because of their exposed locations on the side edges of thecrawler tread, the retention nuts are subjected to the high wearenvironment.

It is therefore an object of the invention to provide means forretaining rotatable hinge pins in place in a crawler tread assembly, theretaining means having minimum exposure to wear. It is an object of theinvention to have hinge pin retention means in a crawler tread assemblywhich can be readily removed, along with the hinge pins, even inconfined areas. Another object of the invention is to minimize theabrasive wear on the hinge pin retention means in an articulated endlesstrack assembly on mobile machinery.

Other aspects, objects, and advantages of the invention will be apparentfrom the following description and the accompanying drawings.

SUMMARY OF THE INVENTION

In accordance with the present invention, the length of a hinge pin andits associated pair of retention elements does not exceed the length ofthe hinge pin chamber formed by the joinder of a pair of crawler pads,such that two retention elements are placed inside the chamber with thehinge pin positioned between them and each retention element isreleasably secured to the surrounding adjacent portion of the crawlerpad. In one embodiment each retention elements is a cylinder orcylindrical segment having a diameter only slightly less than thediameter of the hinge pin chamber, and having a threaded openingextending radially therethrough for securing to the crawler pad by meansof a bolt.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevation view of a continuous miningmachine, including an articulated endless track for moving the machinefrom one location to another;

FIG. 2 is a plan view of the earth contact side of a pair ofinterconnected crawler pads;

FIG. 3 is a side elevation view, corresponding to FIG. 1, of the pair ofinterconnected crawler pads;

FIG. 4 is an end elevation view of the trailing edge of one of thecrawler pads; and

FIG. 5 is an elevation view in cross-section taken along line 5--5 inFIG. 2.

DETAILED DESCRIPTION

Referring now to the drawings in detail and to FIG. 1 in particular, thecontinuous mining machine 11 has a rotary auger 12 supported by arm 13from the front of a mobile chassis or frame 14. The auger 12 engages themine face to cut ore from the mine face. An uptake conveyor 15 and adelivery conveyor 16 move the mined material from the mine face to therear of the mining machine for delivery into suitable vehicles or otherconveyor means for removing the material from the mine. On each side ofthe chassis 14, an endless track assembly 17 is mounted on a drivesprocket 18 and an idler sprocket 19 to provide means for moving themining machine 11 from one place to another along the mine passageway.Each track assembly 17 comprises a plurality of essentially identicalcrawler pads 21 connected in series with each other by hinge pins toform the endless track.

Referring now to FIGS. 2-5, each crawler pad 21 has a leading or forwardedge portion 22 and a trailing or rear edge portion 23, when viewed withthe machine moving ahead. Each leading edge portion 22 has five spacedapart leading hinge knuckles 24, 25, 26, 27, and 28 which extendparallel to each other and the direction of movement of the track. Eachknuckle 24-28 has a bore 29, 30, 31, 32, and 33, respectively, extendingtherethrough perpendicular to the direction of movement of the track.The bores 29-33 are at least generally cylindrical in shape, and on anindividual crawler pad are coaxially aligned with each other.

The trailing edge portion 23 of each crawler pad 21 has four spacedapart trailing hinge knuckles 34, 35, 36 and 37 which extend parallel toeach other and the direction of movement of the track. Each knuckle34-37 has a respective bore 38, 39, 40 or 41 extending therethroughperpendicular to the direction of movement of the track. Bores 38-41 areat least generally cylindrical in shape and have essentially the samediameter as bores 29-33. On an individual crawler pad, bores 38-41 arecoaxially aligned with each other. Hinge knuckles 24-28 are laterallyoffset from hinge knuckles 34-37 on an individual crawler pad such thatthe hinge knuckles 34-37 on the trailing edge of one crawler padinterleave or alternate with the hinge knuckles 24-28 on the leadingedge of the next following crawler pad, as shown in FIG. 2. When theleading knuckles 24-28 of one crawler pad are in engagement withtrailing knuckles 34-37 of another crawler pad, bores 29-33 and bores38-41 are positioned in coaxial alignment with each other, forming asubstantially cylindrical chamber 42 extending through the engaged setof leading and trailing hinge knuckles.

Two hinge or pivot pins 43 and 44, each having a diameter slightlysmaller than the minimum effective diameter of chamber 42, are rotatablypositioned in chamber 42 in coaxial alignment with each other. Hingepins 43 and 44 serve as a pivot pin for the engaged pair of crawlerpads, permitting each of the crawler pads to hinge about the hinge pins.The total length of hinge pins 43 and 44 is less than the length ofchamber 42 along its longitudinal axis, permitting threaded retentionnuts 45 and 46 to be positioned completely within chamber 42 with hingepins 43 and 44 therebetween. Retention nut 45 is completely encircled byhinge knuckle 24, while retention nut 46 is completely encircled byhinge knuckle 28. Each of nuts 45 and 46 is a cylindrical segment, withthe diameter of the cylindrical surface being substantially equal to,but slightly smaller than the minimum diameter of bores 29 and 33. Eachof nuts 45 and 46 has a threaded hole extending radially therethrough. Athreaded bolt 47 is positioned in hole 48 in hinge knuckle 24 such thatbolt 47 extends into threaded engagement with retention nut 45.Similarly, a threaded bolt 49 is positioned in hole 50 in hinge knuckle28 such that bolt 49 extends into threaded engagement with retention nut46. Holes 48 and 50 are enlarged at the outer ends thereof to permit theheads 51, 52 of bolts 47, 49 to be flush with or recessed below theouter surface of the respective hinge knuckle. The correspondinglycurved surfaces of chamber 42 and nuts 45 and 46 permit greater loadingcontact between nuts 45, 46 and knuckles 24, 28, respectively, when nuts45, 46 are tightened on bolts 47, 49.

Hinge pin 43 has a threaded hole 53, 54 in each end thereof while hingepin 44 has a threaded hole 55, 56 in each of its ends. Threaded holes53, 54, 55 and 56 are sized to be engaged by a threaded male element ofvarious tools commonly found in mines. Such threaded engagement permitsthe hinge pin to be readily pulled from its chamber 42 after at leastone of the retention nuts 45, 46 has been removed. Each crawler pad hasa pair of grouser rib elements 57 and 58 extending outwardly therefrom oengage the earth when that crawler pad is in contact with the earthsurface. Each crawler pad has an opening 59 therethrough to permit theteeth of the drive sprocket 18 and idler sprocket 19 to engage thecrawler pad.

While the invention has been illustrated in terms of a specificembodiment, it is also applicable to many other embodiments. Theretention elements can be a full cylinder instead of a cylindricalsegment. A single hinge pin can be utilized for each set of engagedknuckles instead of the set of two coaxial pins illustrated. The numberof knuckles on the leading and trailing edges of a crawler pan can vary.

I claim:
 1. A crawler pad assembly comprising first and second crawlerpads;each of said crawler pads having a leading edge portion and atrailing edge portion, the leading edge portion of each crawler padhaving a plurality of spaced apart first hinge knuckles extendingparallel to each other, each of said first hinge knuckles having a firstbore extending therethrough, the first bores of a respective crawler padbeing at least substantially cylindrical and coaxially aligned withrespect to each other; the trailing edge portion of each crawler padhaving a plurality of spaced apart second hinge knuckles extendingparallel to each other, each of said second hinge knuckles having asecond bore extending therethrough, the second bores of a respectivecrawler pad being at least substantially cylindrical and coaxiallyaligned with respect to each other, the plurality of spaced apart firsthinge knuckles on a respective crawler pad extending parallel to andoffset from the plurality of spaced apart second hinge knuckles on thesame crawler pad; the plurality of spaced apart first hinge knuckles ofsaid first crawler pad being engaged in alternating relationship withthe plurality of spaced apart second hinge knuckles of said secondcrawler pad, with the first bores of said first crawler pad beingcoaxially aligned with the second bores of said second crawler pad toform a substantially cylindrical chamber extending through the thusengaged first and second hinge knuckles; at least one substantiallycylindrical hinge pin positioned in said substantially cylindricalchamber to thereby pivotally connect said first and second crawler pads;first and second retention elements positioned in said substantiallycylindrical chamber such that each said retention element is completelyencircled by a hinge knuckle to protect the respective retention elementagainst abrasive contact with the ground during movement of the crawlerpad assembly and said at least one hinge pin is located between saidfirst and second retention elements and is retained within saidsubstantially cylindrical chamber by said first and second retentionelements, the total longitudinal length of said at least one hinge pinand said first and second retention elements not exceeding thelongitudinal length of said substantially cylindrical chamber; firstmeans for securing said first retention element to a hinge knucklecompletely encircling said first retention element; and second means forsecuring said second retention element to a hinge knuckle completelyencircling said second retention element.
 2. A crawler pad assemblyaccording to claim 1 wherein each of said first and second retentionelements is a threaded nut, and each of said first and second means forsecuring is a threaded bolt extending from adjacent the outer peripheryof the respective encircling hinge knuckle into threaded engagement withthe associated nut.
 3. A crawler pad assembly in accordance with claim 2wherein each said bolt has a head which is recessed within therespective encircling hinge knuckle.
 4. A crawler pad assembly inaccordance with claim 3 wherein at least a portion of the outer surfaceof each said nut is a portion of a cylindrical surface with the diameterof the cylindrical surface being slightly smaller than the effectivediameter of the bore in the respective encircling hinge knuckle which ispart of said substantially cylindrical chamber.
 5. A crawler padassembly in accordance with claim 4 wherein said at least one hinge pincomprises a plurality of hinge pins coaxially aligned with each otherwithin said substantially cylindrical chamber.
 6. An articulated endlesstrack assembly comprising a plurality of crawler pads positioned inseries to form an endless track;each of said crawler pads having aleading edge portion and a trailing edge portion, the leading edgeportion of each crawler pad having a plurality of spaced apart firsthinge knuckles extending parallel to each other and to the length ofsaid track, each of said first hinge knuckles having a first boreextending therethrough, the first bores on a respective crawler padbeing at least substantially cylindrical and coaxially aligned withrespect to each other; the trailing edge portion of each crawler padhaving a plurality of spaced apart second hinge knuckles extendingparallel to each other and the length of said track, each of said secondhinge knuckles having a second bore extending therethrough, the secondbores on a respective crawler pad being at least substantiallycylindrical and coaxially aligned with respect to each other, theplurality of spaced apart first hinge knuckles on a respective crawlerpad extending parallel to and offset from the plurality of spaced apartsecond hinge knuckles on the same crawler pad; the plurality of spacedapart first hinge knuckles of each individual crawler pad being engagedin alternating relationship with the plurality of spaced apart secondhinge knuckles of an adjacent individual crawler pad with the respectivefirst and second bores thereof being coaxially aligned with each otherto form in each thus engaged set of first and second hinge knuckles asubstantially cylindrical chamber extending through the respective setof engaged first and second hinge knuckles; a plurality of hinge pinmeans corresponding in number to the number of engaged sets of first andsecond hinge knuckles, each hinge pin means being positioned in arespective substantially cylindrical chamber to thereby pivotallyconnect the respective pair of crawler pads; a plurality of first andsecond retention elements, with each substantially cylindrical chamberhaving a first retention element and a second retention elementpositioned therein such that each said retention element is completelyencircled by a hinge knuckle to protect the respective retention elementagainst abrasive contact with the ground during movement of the trackassembly and each hinge pin means is located between a respective firstretention element and a respective second retention element and isretained within the respective substantially cylindrical chamber by therespective first and second retention elements, the total longitudinallength of each said hinge pin mans and its associated pair of retentionelements being no greater than the longitudinal length of the respectivesubstantially cylindrical chamber; a plurality of first and secondfastening means, each first fastening means securing a respective firstretention element to a hinge knuckle completely encircling therespective first retention element and each second fastening meanssecuring a respective second retention element to a hinge knucklecompletely encircling the respective retention element.
 7. Anarticulated endless track retention assembly according to claim 6wherein each said first retention element and each said second retentionelement is a threaded nut, and each said first and second fasteningmeans is a threaded bolt extending from adjacent the outer periphery ofthe respective encircling hinge knuckle into threaded engagement withthe associated nut.
 8. An articulated endless track assembly inaccordance with claim 7 wherein each said nut is a cylindrical segmentwith the diameter of the cylindrical surface thereof being slightlysmaller than the effective diameter of the bore in the respectiveencircling hinge knuckle which is part of the respective substantiallycylindrical chamber.
 9. An articulated endless track assembly inaccordance with claim 7 wherein each said bolt has a head which isrecessed within the respective encircling hinge knuckle.
 10. Anarticulated endless track assembly in accordance with claim 9 wherein atleast a portion of the outer surface of each said nut is a portion of acylindrical surface with the diameter of the cylindrical surface beingslightly smaller than the effective diameter of the bore in therespective encircling hinge knuckle which is part of the respectivesubstantially cylindrical chamber.
 11. A crawler pad assembly inaccordance with claim 10 wherein each said hinge pin means comprises aplurality of hinge pins coaxially aligned with each other within eachrespective substantially cylindrical chamber.